Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fd90357d9b93863…

MALICIOUS

PDF

91.0 KB Created: 2021-08-10 15:51:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: a1c4aea0e34852389d12fa09793104cb SHA-1: 2f3678e9777ba84dffd7aeeace38eaeb9b73ff8c SHA-256: 4fd90357d9b938635a715742c0b63b6f8b50c941c9be21babe836c772fc59bb4
204 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous links to external PDFs hosted on compromised WordPress sites and disposable hosting, suggesting a link farm designed to distribute malicious content. The heuristic 'SE_INVOICE_LURE' indicates the document's content is intended to deceive the user into clicking these links. While no scripts were directly extracted, the nature of the links and the ML classification strongly suggest this PDF is a downloader for further malicious payloads, likely exploiting PDF vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9913

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://synersys.fr/contenu/file/63840045951.pdf In PDF document text
    • http://dh-cell.com/ckfinder/userfiles/files/bibufaxakerewitejigot.pdfIn PDF document text
    • https://maclashoes.it/file/kukojobewuzagemejimigoma.pdfIn PDF document text
    • http://skybuildinfraprojects.com/uploads/60987120085.pdfIn PDF document text
    • http://www.kzhep.in.ua/wp-content/plugins/super-forms/uploads/php/files/97v1l5b6bakr66iff6q5gcv215/57978323189.pdfIn PDF document text
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/f340c5826102ffd49e3f8229d6cd6980/49392586439.pdfIn PDF document text
    • https://www.letspassdriving.co.uk/wp-content/plugins/super-forms/uploads/php/files/dm67ll67q3fc0clc5g9ct9dhf5/85524178770.pdfIn PDF document text
    • http://astro2sphere.com/admin/images/file/kemifamaxoratutedez.pdfIn PDF document text
    • http://imagespa.mx/wp-content/plugins/formcraft/file-upload/server/content/files/160d8b1bf0276f---23792771708.pdfIn PDF document text
    • http://ddaengshop.com/ckupload/files/zomuze.pdfIn PDF document text
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/160dec4db1293d---vibalike.pdfIn PDF document text
    • http://www.ximangsongthao.com.vn/app/webroot/uploads/files/18785259908.pdfIn PDF document text
    • https://storage-in-motion.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bdc7de92834---bufevo.pdfIn PDF document text
    • https://alkalacarservice.com/public_html/userfiles/file/39627843334.pdfIn PDF document text
    • http://transbur.ru/admin/ckfinder/userfiles/files/sepififebezi.pdfIn PDF document text
    • http://lushexperiences.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076eef391cd6---31454761644.pdfIn PDF document text
    • http://lmalaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/sebozozesomosedodopaze.pdfIn PDF document text
    • https://skyfireconsulting.com/wp-content/plugins/super-forms/uploads/php/files/gjif4ssm8e0vrvftdkuc3ipg46/zumaxo.pdfIn PDF document text
    • http://xn--m1age8bh.xn--p1ai/files/file/95371125968.pdfIn PDF document text
    • http://dom-nenilovo.ru/wp-content/plugins/super-forms/uploads/php/files/1087d3630af7c574500d3a449ead7803/31642772681.pdfIn PDF document text
    • https://garraldaarquitectura.com/garralda_userfiles/files/derolujazebejuboj.pdfIn PDF document text
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/65584697819.pdfIn PDF document text
    • https://people11people.gr/uploads/File/gufidolanerisiman.pdfIn PDF document text
    • http://halvani.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077f65ab6235---sikopomav.pdfIn PDF document text
    • http://ge-mak.com/files/wiwamo.pdfIn PDF document text
    • https://apparel.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/3f29b903b733b1c46a8b270c5ae0bef4/95858490039.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=best+debt+collection+agency+for+small+businessPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001006e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1006E 11228 bytes
SHA-256: 6d4dbc28d3e2594c0aa470bfae61f4cc3cfcbe28a366db292218b23d6d8ad585
font_01_sfnt_off00011a92.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A92 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000132a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x132A4 16660 bytes
SHA-256: cf4ec2bbfe3f350f892c32d3197cfcc6b73c8688f083f9e29e5a77b34a0d0cd0